Manually operated and electrically powered pencil sharpeners are well known. When a pencil is inserted through a pencil-receiving aperture of a pencil sharpener's housing, the pencil enters a sharpening assembly, which cuts an outer layer typically composed of wood. The cutting process exposes and sharpens an inner core, which is often composed of graphite.
Typically, electric pencil sharpeners have a sharpening assembly including a rotary mechanism, which is rotated by a motor and cutter mechanism, which is operated by the rotary mechanism. The rotary mechanism and cutter mechanism typically rotate in relatively opposite direction. Most pencil sharpeners carry a cutting blade or plurality of cutting blades on the rotary mechanism.
Blades in pencil sharpeners are typically used to sharpen pencils with varying hardness. The combination of graphite, wood, and composite materials in pencils wear down the pencil sharpener blades resulting in increasingly dull blades and increased blade surface roughness through normal use. Pencil sharpeners are also often manipulated by young users who may knowingly or unknowingly damage the sharpener by inserting into the pencil-receiving aperture inappropriate objects that are much harder than pencils, such as pens, paperclips and mechanical pencils. The surface roughness and sharpness of the blades may be negatively affected by the insertion of such inappropriate objects. Dulled blades and increased surface roughness often result in deleterious effects to the writing instruments being sharpened. For example, as the pencil sharpener blades dull and the surface roughness increases, the smoothness of the cut, sharpness of the pencil tip and uniformity of the cut may be deleteriously affected. Pencil shavings and graphite particles often adhere more so to the surface of pencil sharpener blades that have been dulled and have greater surface roughness.
Typically, pencil sharpeners are heavily used mechanical devices, especially in schooling and drafting environments. Over time, as in the case with most heavily used mechanical devices, the mechanical elements of pencil sharpeners become worn.
It would be desirable for a pencil sharpener to have a blade with increased durability to regular and inappropriate use. It would be further desirable for a pencil sharpener to have a blade that would stay sharper longer while deterring the adherence of pencil shavings and graphite particles to the blade surface. It would be further desirable for a pencil sharpening blade to resist an increase in surface roughness through normal and abnormal use.